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Tag: freezing

  • Liquid Flow on Pluto

    Liquid Flow on Pluto

    When New Horizons flew by Pluto, the dwarf planet’s bright heart-shaped glacier at Sputnik Planitia garnered much attention. Now scientists think they’ve found evidence that liquid has flowed recently there. In a new study, they argue that dark regions near the glacier’s edge are likely places where liquid nitrogen flows up through the nitrogen ice and spreads in a magma-like process.

    Close-up images of Sputnik Planitia, showing dark regions (highlighted in the red box) where glacial-melt liquid nitrogen may be reaching the surface.
    Close-up images of Sputnik Planitia, showing dark regions (highlighted in the red box) where glacial-melt liquid nitrogen may be reaching the surface.

    At Pluto’s conditions, liquid nitrogen is less dense than its solid form (unlike on Earth), so any melted liquid from the glacier works its way toward the surface. That would happen through faults and cracks, the same way that buoyant magma rises through the Earth’s crust.

    The team broke this trek down step-by-step and analyzed how nitrogen could melt in the first place, how it would rise and flow at the surface, and how long it would take for the liquid to re-freeze. They concluded that this cryovolcanism is plausible and may occur not just on Pluto but on other cold worlds like Triton and Eris. (Image credit: NASA/Johns Hopkins APL/SwRI; research credit: S. Stern et al.; via Gizmodo)

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  • Freezing Via Ice Bridge

    Freezing Via Ice Bridge

    For frost to spread on a surface, individual water droplets freeze and then spread the freezing front to a nearby droplet. Frequently that happens through an ice bridge that connects one droplet to the next. On hydrophilic surfaces, the bridge grows along the surface, slowly connected one droplet to the next and the next until the entire surface is covered in frost. On superhydrophobic surfaces, frost still spreads via ice bridge, but those ice bridges are suspended in the air, cantilevered out from the frozen droplet. You can watch the process in the image below.

    The researchers found that frost was later to form and slower to spread on these superhydrophobic surfaces, which could be valuable for applications like the heat exchanger found in heat pumps. Once a heat exchanger’s finned surface is frost-covered, its efficiency plummets. The team suggests that coating these surfaces to be superhydrophobic could help keep them operating efficiently longer in cold and humid conditions. (Image credit: frost – K. Shimizu, experiment – S. Yang et al.; research credit: S. Yang et al.; via Physics World)

    Animation of a suspended ice bridge growing between water droplets on a superhydrophobic surface.
    Animation of a suspended ice bridge growing between water droplets on a superhydrophobic surface.
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  • Mirabilite Mounds at Great Salt Lake

    Mirabilite Mounds at Great Salt Lake

    In cold weather, a new geological feature has shown up at Utah’s Great Salt Lake in the last decade. These salty mirabilite mounds form terraced crystals that resemble Yellowstone’s Mammoth Hot Springs.

    Diagram showing salty springs feeding upward through layers of mirabilite to form a mound aboveground.
    Diagram showing how a salt-laden spring pushing upward through the mirabilite layer can then form mounds at the surface when the dissolved mirabilite recrystallizes after the water evaporates.

    Mirabilite is hydrated sodium sulfate (as opposed to the sodium chloride of table salt). The structures form when upwelling spring water partially dissolves the layer of mirabilite found beneath the lake bed. That sulfate-laden water rises to the surface, where it freezes into the crystals seen here.

    A timelapse showing mirabilite mounds forming.
    A timelapse showing the formation of mirabilite mounds.

    When temperatures rise above freezing, the water in the mirabilite evaporates, leaving behind white, powdery thenardite. (Video credit: Great Salt Lake Institute; image credit: Utah Geological Survey)

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  • Featured Video Play Icon

    “Frozen Waves”

    Photographer Jan Erik Waider is a master of capturing incredible landscape imagery. In these videos, he uses a drone to film waves in the Baltic Sea gently undulating polygonal slabs of ice on the ocean surface. The interplay of light, color, and motion looks almost surreal, but nature is better than we credit at making imagery too good to look away from. (Video and image credit: J. Waider/NorthLandscapes; via Colossal)

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  • A Fungus That Freezes Water

    A Fungus That Freezes Water

    Although water can freeze below 0 degrees Celsius, it requires a little help–in the form of a nucleation site–to do so. Often temperatures must dip well below 0 degrees Celsius for droplets to become ice. But a new study shows that at least one fungus forms proteins that help the process along.

    The proteins come from the Mortierellaceae  fungal family, by way of a bacterial species some hundreds of thousands of years ago or more. In experiments, adding the fungal protein helped water freeze 10 or more degrees Celsius sooner than it otherwise would.

    The authors note that there are many possible applications for this freezing additive; it could help preserve food or cells without requiring lower freezing temperatures that could damage delicate tissues. It could also serve as a cloud seeding chemical in place of toxic silver iodide particles. (Image and research credit: R. Eufemio et al.; via Gizmodo; see also V. Tech)

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  • “Quiet Pulse” and “Another World”

    “Quiet Pulse” and “Another World”

    Light shines dimly through the wall of an ice cave in this photograph by Marie-Line Dentler. Shaped by melting, pressure, freezing, and fracture, these structures are dynamic and ethereal. (Image credit: M. Dentler; via Colossal)

    Detail of an ice cave in Iceland, by Marie-Line Dentler.
    View in an ice cave by Marie-Line Dentler.
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  • Aging Salty Ice

    Aging Salty Ice

    When ice forms in salty water, it starts out mushy and porous. Salt does not freeze neatly into ice’s crystalline structure, so the forming ice has pores and gaps where salty brine gathers. As the ice ages, more brine is pushed out and gradually convects downward, due to its greater density. Over time, this makes the ice layer thinner but more solid, with fewer pores. You can see a timelapse of the process in a laboratory experiment below. (Image credit: sea ice – C. Matias, experiment – F. Wang et al.; research credit: F. Wang et al.)

    Timelapse of ice forming and aging in salt water over the course of ~16 days.
  • Milano Cortina 2026: Cortina Sliding Center

    Milano Cortina 2026: Cortina Sliding Center

    This year’s sliding events–bobsleigh, luge, and skeleton–will take place at the brand-new Cortina Sliding Center. Built on the site of a historic sliding track, this new venue came together in only the last couple of years. It features a state-of-the-art refrigeration system that pumps a mixture of water and ethylene glycol beneath the track surface to keep the ice properly chilled. Each section of the track is continuously monitored to optimize the flow rate, temperature, and pressure of the refrigerant to keep the track at maximum performance while minimizing environmental impact.

    According to the designers, it’s the first competition track to use a glycol-based refrigeration system, which should be more sustainable than the ammonia-based systems used elsewhere. For a sense of what a run is like, check out this skeleton driver POV run from the facility’s shakedown competition last year. (Image credit: LMSteel; video credit: tuff sledding)

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  • “Moment of Creation”

    “Moment of Creation”

    Bubbles caught in ice resemble the growth of a cellular organism in this photograph of Tatiewa Lake in Japan, taken by Soichiro Moriyama. When water freezes, gases dissolved in it come out of solution, but depending on the speed and direction of freezing, these bubbles do not always escape before ice forms around them, freezing pockets of gas within the ice’s structure. (Image credit: S. Moriyama; via ILPOTY)

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  • “Melting Snowflake”

    “Melting Snowflake”

    It’s hard to preserve something as ephemeral as a snowflake, as seen in this microphotograph by Michael Robert Peres. Despite the old adage, it is possible to make identical snowflakes, but it requires mirroring the freezing conditions exactly, including both temperature and humidity. Here, the snowflake’s crystalline structure survives as a ghost in a melting droplet. (Image credit: M. Peres; via Ars Technica)

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